[S390] rework idle code
Whenever the cpu loads an enabled wait PSW it will appear as idle to the
underlying host system. The code in default_idle calls vtime_stop_cpu
which does the necessary voodoo to get the cpu time accounting right.
The udelay code just loads an enabled wait PSW. To correct this rework
the vtime_stop_cpu/vtime_start_cpu logic and move the difficult parts
to entry[64].S, vtime_stop_cpu can now be called from anywhere and
vtime_start_cpu is gone. The correction of the cpu time during wakeup
from an enabled wait PSW is done with a critical section in entry[64].S.
As vtime_start_cpu is gone, s390_idle_check can be removed as well.
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
diff --git a/arch/s390/include/asm/cputime.h b/arch/s390/include/asm/cputime.h
index c23c390..24ef186 100644
--- a/arch/s390/include/asm/cputime.h
+++ b/arch/s390/include/asm/cputime.h
@@ -170,24 +170,17 @@
unsigned int sequence;
unsigned long long idle_count;
unsigned long long idle_enter;
+ unsigned long long idle_exit;
unsigned long long idle_time;
int nohz_delay;
};
DECLARE_PER_CPU(struct s390_idle_data, s390_idle);
-void vtime_start_cpu(__u64 int_clock, __u64 enter_timer);
cputime64_t s390_get_idle_time(int cpu);
#define arch_idle_time(cpu) s390_get_idle_time(cpu)
-static inline void s390_idle_check(struct pt_regs *regs, __u64 int_clock,
- __u64 enter_timer)
-{
- if (regs->psw.mask & PSW_MASK_WAIT)
- vtime_start_cpu(int_clock, enter_timer);
-}
-
static inline int s390_nohz_delay(int cpu)
{
return __get_cpu_var(s390_idle).nohz_delay != 0;
diff --git a/arch/s390/include/asm/timer.h b/arch/s390/include/asm/timer.h
index 814243c..e63069b 100644
--- a/arch/s390/include/asm/timer.h
+++ b/arch/s390/include/asm/timer.h
@@ -33,8 +33,8 @@
spinlock_t lock;
__u64 timer; /* last programmed timer */
__u64 elapsed; /* elapsed time of timer expire values */
- __u64 idle; /* temp var for idle */
- int do_spt; /* =1: reprogram cpu timer in idle */
+ __u64 idle_enter; /* cpu timer on idle enter */
+ __u64 idle_exit; /* cpu timer on idle exit */
};
extern void init_virt_timer(struct vtimer_list *timer);
diff --git a/arch/s390/kernel/asm-offsets.c b/arch/s390/kernel/asm-offsets.c
index aeeaf89..ed8c913 100644
--- a/arch/s390/kernel/asm-offsets.c
+++ b/arch/s390/kernel/asm-offsets.c
@@ -8,6 +8,8 @@
#include <linux/kbuild.h>
#include <linux/sched.h>
+#include <asm/cputime.h>
+#include <asm/timer.h>
#include <asm/vdso.h>
#include <asm/pgtable.h>
#include <asm/system.h>
@@ -70,6 +72,12 @@
DEFINE(__CLOCK_MONOTONIC, CLOCK_MONOTONIC);
DEFINE(__CLOCK_REALTIME_RES, MONOTONIC_RES_NSEC);
BLANK();
+ /* idle data offsets */
+ DEFINE(__IDLE_ENTER, offsetof(struct s390_idle_data, idle_enter));
+ DEFINE(__IDLE_EXIT, offsetof(struct s390_idle_data, idle_exit));
+ /* vtimer queue offsets */
+ DEFINE(__VQ_IDLE_ENTER, offsetof(struct vtimer_queue, idle_enter));
+ DEFINE(__VQ_IDLE_EXIT, offsetof(struct vtimer_queue, idle_exit));
/* lowcore offsets */
DEFINE(__LC_EXT_PARAMS, offsetof(struct _lowcore, ext_params));
DEFINE(__LC_EXT_CPU_ADDR, offsetof(struct _lowcore, ext_cpu_addr));
diff --git a/arch/s390/kernel/entry.S b/arch/s390/kernel/entry.S
index 6143521..74ee563 100644
--- a/arch/s390/kernel/entry.S
+++ b/arch/s390/kernel/entry.S
@@ -105,14 +105,14 @@
.macro ADD64 high,low,timer
al \high,\timer
- al \low,\timer+4
+ al \low,4+\timer
brc 12,.+8
ahi \high,1
.endm
.macro SUB64 high,low,timer
sl \high,\timer
- sl \low,\timer+4
+ sl \low,4+\timer
brc 3,.+8
ahi \high,-1
.endm
@@ -471,7 +471,6 @@
jnz io_work # there is work to do (signals etc.)
io_restore:
mvc __LC_RETURN_PSW(8),__PT_PSW(%r11)
- ni __LC_RETURN_PSW+1,0xfd # clean wait state bit
stpt __LC_EXIT_TIMER
lm %r0,%r15,__PT_R0(%r11)
lpsw __LC_RETURN_PSW
@@ -612,6 +611,26 @@
basr %r14,%r1 # call do_extint
j io_return
+/*
+ * Load idle PSW. The second "half" of this function is in cleanup_idle.
+ */
+ENTRY(psw_idle)
+ st %r4,__SF_EMPTY(%r15)
+ basr %r1,0
+ la %r1,psw_idle_lpsw+4-.(%r1)
+ st %r1,__SF_EMPTY+4(%r15)
+ oi __SF_EMPTY+4(%r15),0x80
+ la %r1,.Lvtimer_max-psw_idle_lpsw-4(%r1)
+ stck __IDLE_ENTER(%r2)
+ ltr %r5,%r5
+ stpt __VQ_IDLE_ENTER(%r3)
+ jz psw_idle_lpsw
+ spt 0(%r1)
+psw_idle_lpsw:
+ lpsw __SF_EMPTY(%r15)
+ br %r14
+psw_idle_end:
+
__critical_end:
/*
@@ -673,7 +692,6 @@
TRACE_IRQS_ON
mcck_return:
mvc __LC_RETURN_MCCK_PSW(8),__PT_PSW(%r11) # move return PSW
- ni __LC_RETURN_MCCK_PSW+1,0xfd # clear wait state bit
tm __LC_RETURN_MCCK_PSW+1,0x01 # returning to user ?
jno 0f
lm %r0,%r15,__PT_R0(%r11)
@@ -748,6 +766,8 @@
.long io_tif + 0x80000000
.long io_restore + 0x80000000
.long io_done + 0x80000000
+ .long psw_idle + 0x80000000
+ .long psw_idle_end + 0x80000000
cleanup_critical:
cl %r9,BASED(cleanup_table) # system_call
@@ -766,6 +786,10 @@
jl cleanup_io_tif
cl %r9,BASED(cleanup_table+28) # io_done
jl cleanup_io_restore
+ cl %r9,BASED(cleanup_table+32) # psw_idle
+ jl 0f
+ cl %r9,BASED(cleanup_table+36) # psw_idle_end
+ jl cleanup_idle
0: br %r14
cleanup_system_call:
@@ -849,7 +873,6 @@
jhe 0f
l %r9,12(%r11) # get saved r11 pointer to pt_regs
mvc __LC_RETURN_PSW(8),__PT_PSW(%r9)
- ni __LC_RETURN_PSW+1,0xfd # clear wait state bit
mvc 0(32,%r11),__PT_R8(%r9)
lm %r0,%r7,__PT_R0(%r9)
0: lm %r8,%r9,__LC_RETURN_PSW
@@ -857,11 +880,52 @@
cleanup_io_restore_insn:
.long io_done - 4 + 0x80000000
+cleanup_idle:
+ # copy interrupt clock & cpu timer
+ mvc __IDLE_EXIT(8,%r2),__LC_INT_CLOCK
+ mvc __VQ_IDLE_EXIT(8,%r3),__LC_ASYNC_ENTER_TIMER
+ chi %r11,__LC_SAVE_AREA_ASYNC
+ je 0f
+ mvc __IDLE_EXIT(8,%r2),__LC_MCCK_CLOCK
+ mvc __VQ_IDLE_EXIT(8,%r3),__LC_MCCK_ENTER_TIMER
+0: # check if stck has been executed
+ cl %r9,BASED(cleanup_idle_insn)
+ jhe 1f
+ mvc __IDLE_ENTER(8,%r2),__IDLE_EXIT(%r2)
+ mvc __VQ_IDLE_ENTER(8,%r3),__VQ_IDLE_EXIT(%r3)
+ j 2f
+1: # check if the cpu timer has been reprogrammed
+ ltr %r5,%r5
+ jz 2f
+ spt __VQ_IDLE_ENTER(%r3)
+2: # account system time going idle
+ lm %r9,%r10,__LC_STEAL_TIMER
+ ADD64 %r9,%r10,__IDLE_ENTER(%r2)
+ SUB64 %r9,%r10,__LC_LAST_UPDATE_CLOCK
+ stm %r9,%r10,__LC_STEAL_TIMER
+ mvc __LC_LAST_UPDATE_CLOCK(8),__IDLE_EXIT(%r2)
+ lm %r9,%r10,__LC_SYSTEM_TIMER
+ ADD64 %r9,%r10,__LC_LAST_UPDATE_TIMER
+ SUB64 %r9,%r10,__VQ_IDLE_ENTER(%r3)
+ stm %r9,%r10,__LC_SYSTEM_TIMER
+ mvc __LC_LAST_UPDATE_TIMER(8),__VQ_IDLE_EXIT(%r3)
+ # prepare return psw
+ n %r8,BASED(cleanup_idle_wait) # clear wait state bit
+ l %r9,24(%r11) # return from psw_idle
+ br %r14
+cleanup_idle_insn:
+ .long psw_idle_lpsw + 0x80000000
+cleanup_idle_wait:
+ .long 0xfffdffff
+
/*
* Integer constants
*/
.align 4
-.Lnr_syscalls: .long NR_syscalls
+.Lnr_syscalls:
+ .long NR_syscalls
+.Lvtimer_max:
+ .quad 0x7fffffffffffffff
/*
* Symbol constants
diff --git a/arch/s390/kernel/entry.h b/arch/s390/kernel/entry.h
index 92b1617..4984785 100644
--- a/arch/s390/kernel/entry.h
+++ b/arch/s390/kernel/entry.h
@@ -4,7 +4,8 @@
#include <linux/types.h>
#include <linux/signal.h>
#include <asm/ptrace.h>
-
+#include <asm/cputime.h>
+#include <asm/timer.h>
extern void (*pgm_check_table[128])(struct pt_regs *);
extern void *restart_stack;
@@ -16,6 +17,8 @@
void mcck_int_handler(void);
void restart_int_handler(void);
void restart_call_handler(void);
+void psw_idle(struct s390_idle_data *, struct vtimer_queue *,
+ unsigned long, int);
asmlinkage long do_syscall_trace_enter(struct pt_regs *regs);
asmlinkage void do_syscall_trace_exit(struct pt_regs *regs);
diff --git a/arch/s390/kernel/entry64.S b/arch/s390/kernel/entry64.S
index e33789a..4e1c292 100644
--- a/arch/s390/kernel/entry64.S
+++ b/arch/s390/kernel/entry64.S
@@ -489,7 +489,6 @@
lg %r14,__LC_VDSO_PER_CPU
lmg %r0,%r10,__PT_R0(%r11)
mvc __LC_RETURN_PSW(16),__PT_PSW(%r11)
- ni __LC_RETURN_PSW+1,0xfd # clear wait state bit
stpt __LC_EXIT_TIMER
mvc __VDSO_ECTG_BASE(16,%r14),__LC_EXIT_TIMER
lmg %r11,%r15,__PT_R11(%r11)
@@ -631,6 +630,24 @@
brasl %r14,do_extint
j io_return
+/*
+ * Load idle PSW. The second "half" of this function is in cleanup_idle.
+ */
+ENTRY(psw_idle)
+ stg %r4,__SF_EMPTY(%r15)
+ larl %r1,psw_idle_lpsw+4
+ stg %r1,__SF_EMPTY+8(%r15)
+ larl %r1,.Lvtimer_max
+ stck __IDLE_ENTER(%r2)
+ ltr %r5,%r5
+ stpt __VQ_IDLE_ENTER(%r3)
+ jz psw_idle_lpsw
+ spt 0(%r1)
+psw_idle_lpsw:
+ lpswe __SF_EMPTY(%r15)
+ br %r14
+psw_idle_end:
+
__critical_end:
/*
@@ -696,7 +713,6 @@
lg %r14,__LC_VDSO_PER_CPU
lmg %r0,%r10,__PT_R0(%r11)
mvc __LC_RETURN_MCCK_PSW(16),__PT_PSW(%r11) # move return PSW
- ni __LC_RETURN_MCCK_PSW+1,0xfd # clear wait state bit
tm __LC_RETURN_MCCK_PSW+1,0x01 # returning to user ?
jno 0f
stpt __LC_EXIT_TIMER
@@ -770,6 +786,8 @@
.quad io_tif
.quad io_restore
.quad io_done
+ .quad psw_idle
+ .quad psw_idle_end
cleanup_critical:
clg %r9,BASED(cleanup_table) # system_call
@@ -788,6 +806,10 @@
jl cleanup_io_tif
clg %r9,BASED(cleanup_table+56) # io_done
jl cleanup_io_restore
+ clg %r9,BASED(cleanup_table+64) # psw_idle
+ jl 0f
+ clg %r9,BASED(cleanup_table+72) # psw_idle_end
+ jl cleanup_idle
0: br %r14
@@ -877,7 +899,6 @@
je 0f
lg %r9,24(%r11) # get saved r11 pointer to pt_regs
mvc __LC_RETURN_PSW(16),__PT_PSW(%r9)
- ni __LC_RETURN_PSW+1,0xfd # clear wait state bit
mvc 0(64,%r11),__PT_R8(%r9)
lmg %r0,%r7,__PT_R0(%r9)
0: lmg %r8,%r9,__LC_RETURN_PSW
@@ -885,6 +906,42 @@
cleanup_io_restore_insn:
.quad io_done - 4
+cleanup_idle:
+ # copy interrupt clock & cpu timer
+ mvc __IDLE_EXIT(8,%r2),__LC_INT_CLOCK
+ mvc __VQ_IDLE_EXIT(8,%r3),__LC_ASYNC_ENTER_TIMER
+ cghi %r11,__LC_SAVE_AREA_ASYNC
+ je 0f
+ mvc __IDLE_EXIT(8,%r2),__LC_MCCK_CLOCK
+ mvc __VQ_IDLE_EXIT(8,%r3),__LC_MCCK_ENTER_TIMER
+0: # check if stck & stpt have been executed
+ clg %r9,BASED(cleanup_idle_insn)
+ jhe 1f
+ mvc __IDLE_ENTER(8,%r2),__IDLE_EXIT(%r2)
+ mvc __VQ_IDLE_ENTER(8,%r3),__VQ_IDLE_EXIT(%r3)
+ j 2f
+1: # check if the cpu timer has been reprogrammed
+ ltr %r5,%r5
+ jz 2f
+ spt __VQ_IDLE_ENTER(%r3)
+2: # account system time going idle
+ lg %r9,__LC_STEAL_TIMER
+ alg %r9,__IDLE_ENTER(%r2)
+ slg %r9,__LC_LAST_UPDATE_CLOCK
+ stg %r9,__LC_STEAL_TIMER
+ mvc __LC_LAST_UPDATE_CLOCK(8),__IDLE_EXIT(%r2)
+ lg %r9,__LC_SYSTEM_TIMER
+ alg %r9,__LC_LAST_UPDATE_TIMER
+ slg %r9,__VQ_IDLE_ENTER(%r3)
+ stg %r9,__LC_SYSTEM_TIMER
+ mvc __LC_LAST_UPDATE_TIMER(8),__VQ_IDLE_EXIT(%r3)
+ # prepare return psw
+ nihh %r8,0xfffd # clear wait state bit
+ lg %r9,48(%r11) # return from psw_idle
+ br %r14
+cleanup_idle_insn:
+ .quad psw_idle_lpsw
+
/*
* Integer constants
*/
@@ -893,6 +950,8 @@
.quad __critical_start
.Lcritical_length:
.quad __critical_end - __critical_start
+.Lvtimer_max:
+ .quad 0x7fffffffffffffff
#if defined(CONFIG_KVM) || defined(CONFIG_KVM_MODULE)
diff --git a/arch/s390/kernel/irq.c b/arch/s390/kernel/irq.c
index b9a7fdd..09a014c 100644
--- a/arch/s390/kernel/irq.c
+++ b/arch/s390/kernel/irq.c
@@ -219,8 +219,6 @@
code = (unsigned short) ext_int_code;
old_regs = set_irq_regs(regs);
- s390_idle_check(regs, S390_lowcore.int_clock,
- S390_lowcore.async_enter_timer);
irq_enter();
if (S390_lowcore.int_clock >= S390_lowcore.clock_comparator)
/* Serve timer interrupts first. */
diff --git a/arch/s390/kernel/nmi.c b/arch/s390/kernel/nmi.c
index 0fd2e86..8c372ca 100644
--- a/arch/s390/kernel/nmi.c
+++ b/arch/s390/kernel/nmi.c
@@ -254,8 +254,6 @@
int umode;
nmi_enter();
- s390_idle_check(regs, S390_lowcore.mcck_clock,
- S390_lowcore.mcck_enter_timer);
kstat_cpu(smp_processor_id()).irqs[NMI_NMI]++;
mci = (struct mci *) &S390_lowcore.mcck_interruption_code;
mcck = &__get_cpu_var(cpu_mcck);
diff --git a/arch/s390/kernel/process.c b/arch/s390/kernel/process.c
index e795933..78b3c14 100644
--- a/arch/s390/kernel/process.c
+++ b/arch/s390/kernel/process.c
@@ -77,13 +77,8 @@
local_irq_enable();
return;
}
- trace_hardirqs_on();
- /* Don't trace preempt off for idle. */
- stop_critical_timings();
- /* Stop virtual timer and halt the cpu. */
+ /* Halt the cpu and keep track of cpu time accounting. */
vtime_stop_cpu();
- /* Reenable preemption tracer. */
- start_critical_timings();
}
void cpu_idle(void)
diff --git a/arch/s390/kernel/smp.c b/arch/s390/kernel/smp.c
index 6db8526..afd6e51 100644
--- a/arch/s390/kernel/smp.c
+++ b/arch/s390/kernel/smp.c
@@ -972,22 +972,16 @@
static ssize_t show_idle_count(struct device *dev,
struct device_attribute *attr, char *buf)
{
- struct s390_idle_data *idle;
+ struct s390_idle_data *idle = &per_cpu(s390_idle, dev->id);
unsigned long long idle_count;
unsigned int sequence;
- idle = &per_cpu(s390_idle, dev->id);
-repeat:
- sequence = idle->sequence;
- smp_rmb();
- if (sequence & 1)
- goto repeat;
- idle_count = idle->idle_count;
- if (idle->idle_enter)
- idle_count++;
- smp_rmb();
- if (idle->sequence != sequence)
- goto repeat;
+ do {
+ sequence = ACCESS_ONCE(idle->sequence);
+ idle_count = ACCESS_ONCE(idle->idle_count);
+ if (ACCESS_ONCE(idle->idle_enter))
+ idle_count++;
+ } while ((sequence & 1) || (idle->sequence != sequence));
return sprintf(buf, "%llu\n", idle_count);
}
static DEVICE_ATTR(idle_count, 0444, show_idle_count, NULL);
@@ -995,24 +989,18 @@
static ssize_t show_idle_time(struct device *dev,
struct device_attribute *attr, char *buf)
{
- struct s390_idle_data *idle;
- unsigned long long now, idle_time, idle_enter;
+ struct s390_idle_data *idle = &per_cpu(s390_idle, dev->id);
+ unsigned long long now, idle_time, idle_enter, idle_exit;
unsigned int sequence;
- idle = &per_cpu(s390_idle, dev->id);
- now = get_clock();
-repeat:
- sequence = idle->sequence;
- smp_rmb();
- if (sequence & 1)
- goto repeat;
- idle_time = idle->idle_time;
- idle_enter = idle->idle_enter;
- if (idle_enter != 0ULL && idle_enter < now)
- idle_time += now - idle_enter;
- smp_rmb();
- if (idle->sequence != sequence)
- goto repeat;
+ do {
+ now = get_clock();
+ sequence = ACCESS_ONCE(idle->sequence);
+ idle_time = ACCESS_ONCE(idle->idle_time);
+ idle_enter = ACCESS_ONCE(idle->idle_enter);
+ idle_exit = ACCESS_ONCE(idle->idle_exit);
+ } while ((sequence & 1) || (idle->sequence != sequence));
+ idle_time += idle_enter ? ((idle_exit ? : now) - idle_enter) : 0;
return sprintf(buf, "%llu\n", idle_time >> 12);
}
static DEVICE_ATTR(idle_time_us, 0444, show_idle_time, NULL);
diff --git a/arch/s390/kernel/vtime.c b/arch/s390/kernel/vtime.c
index 7bacee9..277ea71 100644
--- a/arch/s390/kernel/vtime.c
+++ b/arch/s390/kernel/vtime.c
@@ -26,6 +26,7 @@
#include <asm/irq_regs.h>
#include <asm/cputime.h>
#include <asm/irq.h>
+#include "entry.h"
static DEFINE_PER_CPU(struct vtimer_queue, virt_cpu_timer);
@@ -123,153 +124,53 @@
}
EXPORT_SYMBOL_GPL(account_system_vtime);
-void __kprobes vtime_start_cpu(__u64 int_clock, __u64 enter_timer)
-{
- struct s390_idle_data *idle = &__get_cpu_var(s390_idle);
- struct vtimer_queue *vq = &__get_cpu_var(virt_cpu_timer);
- __u64 idle_time, expires;
-
- if (idle->idle_enter == 0ULL)
- return;
-
- /* Account time spent with enabled wait psw loaded as idle time. */
- idle_time = int_clock - idle->idle_enter;
- account_idle_time(idle_time);
- S390_lowcore.steal_timer +=
- idle->idle_enter - S390_lowcore.last_update_clock;
- S390_lowcore.last_update_clock = int_clock;
-
- /* Account system time spent going idle. */
- S390_lowcore.system_timer += S390_lowcore.last_update_timer - vq->idle;
- S390_lowcore.last_update_timer = enter_timer;
-
- /* Restart vtime CPU timer */
- if (vq->do_spt) {
- /* Program old expire value but first save progress. */
- expires = vq->idle - enter_timer;
- expires += get_vtimer();
- set_vtimer(expires);
- } else {
- /* Don't account the CPU timer delta while the cpu was idle. */
- vq->elapsed -= vq->idle - enter_timer;
- }
-
- idle->sequence++;
- smp_wmb();
- idle->idle_time += idle_time;
- idle->idle_enter = 0ULL;
- idle->idle_count++;
- smp_wmb();
- idle->sequence++;
-}
-
void __kprobes vtime_stop_cpu(void)
{
struct s390_idle_data *idle = &__get_cpu_var(s390_idle);
struct vtimer_queue *vq = &__get_cpu_var(virt_cpu_timer);
- psw_t psw;
+ unsigned long long idle_time;
+ unsigned long psw_mask;
+
+ trace_hardirqs_on();
+ /* Don't trace preempt off for idle. */
+ stop_critical_timings();
/* Wait for external, I/O or machine check interrupt. */
- psw.mask = psw_kernel_bits | PSW_MASK_WAIT |
- PSW_MASK_DAT | PSW_MASK_IO | PSW_MASK_EXT | PSW_MASK_MCHECK;
-
+ psw_mask = psw_kernel_bits | PSW_MASK_WAIT | PSW_MASK_DAT |
+ PSW_MASK_IO | PSW_MASK_EXT | PSW_MASK_MCHECK;
idle->nohz_delay = 0;
- /* Check if the CPU timer needs to be reprogrammed. */
- if (vq->do_spt) {
- __u64 vmax = VTIMER_MAX_SLICE;
- /*
- * The inline assembly is equivalent to
- * vq->idle = get_cpu_timer();
- * set_cpu_timer(VTIMER_MAX_SLICE);
- * idle->idle_enter = get_clock();
- * __load_psw_mask(psw_kernel_bits | PSW_MASK_WAIT |
- * PSW_MASK_DAT | PSW_MASK_IO |
- * PSW_MASK_EXT | PSW_MASK_MCHECK);
- * The difference is that the inline assembly makes sure that
- * the last three instruction are stpt, stck and lpsw in that
- * order. This is done to increase the precision.
- */
- asm volatile(
-#ifndef CONFIG_64BIT
- " basr 1,0\n"
- "0: ahi 1,1f-0b\n"
- " st 1,4(%2)\n"
-#else /* CONFIG_64BIT */
- " larl 1,1f\n"
- " stg 1,8(%2)\n"
-#endif /* CONFIG_64BIT */
- " stpt 0(%4)\n"
- " spt 0(%5)\n"
- " stck 0(%3)\n"
-#ifndef CONFIG_64BIT
- " lpsw 0(%2)\n"
-#else /* CONFIG_64BIT */
- " lpswe 0(%2)\n"
-#endif /* CONFIG_64BIT */
- "1:"
- : "=m" (idle->idle_enter), "=m" (vq->idle)
- : "a" (&psw), "a" (&idle->idle_enter),
- "a" (&vq->idle), "a" (&vmax), "m" (vmax), "m" (psw)
- : "memory", "cc", "1");
- } else {
- /*
- * The inline assembly is equivalent to
- * vq->idle = get_cpu_timer();
- * idle->idle_enter = get_clock();
- * __load_psw_mask(psw_kernel_bits | PSW_MASK_WAIT |
- * PSW_MASK_DAT | PSW_MASK_IO |
- * PSW_MASK_EXT | PSW_MASK_MCHECK);
- * The difference is that the inline assembly makes sure that
- * the last three instruction are stpt, stck and lpsw in that
- * order. This is done to increase the precision.
- */
- asm volatile(
-#ifndef CONFIG_64BIT
- " basr 1,0\n"
- "0: ahi 1,1f-0b\n"
- " st 1,4(%2)\n"
-#else /* CONFIG_64BIT */
- " larl 1,1f\n"
- " stg 1,8(%2)\n"
-#endif /* CONFIG_64BIT */
- " stpt 0(%4)\n"
- " stck 0(%3)\n"
-#ifndef CONFIG_64BIT
- " lpsw 0(%2)\n"
-#else /* CONFIG_64BIT */
- " lpswe 0(%2)\n"
-#endif /* CONFIG_64BIT */
- "1:"
- : "=m" (idle->idle_enter), "=m" (vq->idle)
- : "a" (&psw), "a" (&idle->idle_enter),
- "a" (&vq->idle), "m" (psw)
- : "memory", "cc", "1");
- }
+ /* Call the assembler magic in entry.S */
+ psw_idle(idle, vq, psw_mask, !list_empty(&vq->list));
+
+ /* Reenable preemption tracer. */
+ start_critical_timings();
+
+ /* Account time spent with enabled wait psw loaded as idle time. */
+ idle->sequence++;
+ smp_wmb();
+ idle_time = idle->idle_exit - idle->idle_enter;
+ idle->idle_time += idle_time;
+ idle->idle_enter = idle->idle_exit = 0ULL;
+ idle->idle_count++;
+ account_idle_time(idle_time);
+ smp_wmb();
+ idle->sequence++;
}
cputime64_t s390_get_idle_time(int cpu)
{
- struct s390_idle_data *idle;
- unsigned long long now, idle_time, idle_enter;
+ struct s390_idle_data *idle = &per_cpu(s390_idle, cpu);
+ unsigned long long now, idle_enter, idle_exit;
unsigned int sequence;
- idle = &per_cpu(s390_idle, cpu);
-
- now = get_clock();
-repeat:
- sequence = idle->sequence;
- smp_rmb();
- if (sequence & 1)
- goto repeat;
- idle_time = 0;
- idle_enter = idle->idle_enter;
- if (idle_enter != 0ULL && idle_enter < now)
- idle_time = now - idle_enter;
- smp_rmb();
- if (idle->sequence != sequence)
- goto repeat;
- return idle_time;
+ do {
+ now = get_clock();
+ sequence = ACCESS_ONCE(idle->sequence);
+ idle_enter = ACCESS_ONCE(idle->idle_enter);
+ idle_exit = ACCESS_ONCE(idle->idle_exit);
+ } while ((sequence & 1) || (idle->sequence != sequence));
+ return idle_enter ? ((idle_exit ? : now) - idle_enter) : 0;
}
/*
@@ -346,7 +247,6 @@
}
spin_unlock(&vq->lock);
- vq->do_spt = list_empty(&cb_list);
do_callbacks(&cb_list);
/* next event is first in list */
@@ -355,8 +255,7 @@
if (!list_empty(&vq->list)) {
event = list_first_entry(&vq->list, struct vtimer_list, entry);
next = event->expires;
- } else
- vq->do_spt = 0;
+ }
spin_unlock(&vq->lock);
/*
* To improve precision add the time spent by the
diff --git a/arch/s390/lib/delay.c b/arch/s390/lib/delay.c
index db92f04..9f1f71e 100644
--- a/arch/s390/lib/delay.c
+++ b/arch/s390/lib/delay.c
@@ -13,6 +13,7 @@
#include <linux/irqflags.h>
#include <linux/interrupt.h>
#include <asm/div64.h>
+#include <asm/timer.h>
void __delay(unsigned long loops)
{
@@ -28,36 +29,33 @@
static void __udelay_disabled(unsigned long long usecs)
{
- unsigned long mask, cr0, cr0_saved;
- u64 clock_saved;
- u64 end;
+ unsigned long cr0, cr6, new;
+ u64 clock_saved, end;
- mask = psw_kernel_bits | PSW_MASK_DAT | PSW_MASK_WAIT |
- PSW_MASK_EXT | PSW_MASK_MCHECK;
end = get_clock() + (usecs << 12);
clock_saved = local_tick_disable();
- __ctl_store(cr0_saved, 0, 0);
- cr0 = (cr0_saved & 0xffff00e0) | 0x00000800;
- __ctl_load(cr0 , 0, 0);
+ __ctl_store(cr0, 0, 0);
+ __ctl_store(cr6, 6, 6);
+ new = (cr0 & 0xffff00e0) | 0x00000800;
+ __ctl_load(new , 0, 0);
+ new = 0;
+ __ctl_load(new, 6, 6);
lockdep_off();
do {
set_clock_comparator(end);
- trace_hardirqs_on();
- __load_psw_mask(mask);
+ vtime_stop_cpu();
local_irq_disable();
} while (get_clock() < end);
lockdep_on();
- __ctl_load(cr0_saved, 0, 0);
+ __ctl_load(cr0, 0, 0);
+ __ctl_load(cr6, 6, 6);
local_tick_enable(clock_saved);
}
static void __udelay_enabled(unsigned long long usecs)
{
- unsigned long mask;
- u64 clock_saved;
- u64 end;
+ u64 clock_saved, end;
- mask = psw_kernel_bits | PSW_MASK_WAIT | PSW_MASK_EXT | PSW_MASK_IO;
end = get_clock() + (usecs << 12);
do {
clock_saved = 0;
@@ -65,8 +63,7 @@
clock_saved = local_tick_disable();
set_clock_comparator(end);
}
- trace_hardirqs_on();
- __load_psw_mask(mask);
+ vtime_stop_cpu();
local_irq_disable();
if (clock_saved)
local_tick_enable(clock_saved);
diff --git a/drivers/s390/cio/cio.c b/drivers/s390/cio/cio.c
index dc67c39..a49c46c 100644
--- a/drivers/s390/cio/cio.c
+++ b/drivers/s390/cio/cio.c
@@ -601,8 +601,6 @@
struct pt_regs *old_regs;
old_regs = set_irq_regs(regs);
- s390_idle_check(regs, S390_lowcore.int_clock,
- S390_lowcore.async_enter_timer);
irq_enter();
__this_cpu_write(s390_idle.nohz_delay, 1);
if (S390_lowcore.int_clock >= S390_lowcore.clock_comparator)